In a method of manufacturing a circuit module (an electronic component module) disclosed in Japanese Unexamined Patent Application Publication No. 2004-172176 (Patent Document 1), after a sealing resin has been formed, and before a shield layer that coats the sealing resin is formed, grooves are formed by half-cutting an aggregate substrate (cutting halfway through the aggregate substrate) using a dicer or the like along separation lines along which the aggregate substrate is to be singulated into circuit modules. A top surface of the sealing resin is coated with a conductive resin, and the grooves that have been formed are filled with the conductive resin. The grooves that have been filled with the conductive resin are fully cut (the aggregate substrate is fully cut) using a dicer or the like, so that the aggregate substrate is singulated into circuit modules each having a top surface and side surfaces on which the shield layer is formed.